Wetsuits, drysuits and survival suits have been used worldwide for many years for water sports and water safety to provide thermal insulation for persons exposed to cold air, wind and rain, and/or immersed in cold water. Wetsuits are generally comprised of neoprene foam, designed to be tightly fitting to the user's body, which foam is an elastomeric polymer (polychloroprene) having a density range of 0.15-0.25 g/cc. Drysuits are generally comprised of non-stretch, loose fitting material, worn over an undergarment. Survival suits, which generally must be donned quickly during an emergency, are loosely fitting over a user's clothing, with tight seals at the neck, wrists and ankles.
A plethora of patents have been filed with respect to suit materials, suit entry and exit and sealing against skin to stop or minimize water intrusion. A key aspect of wetsuits is to minimize water intrusion at the wrist, ankle and neck. Interestingly, there is a perception amongst some users that it is acceptable to allow water entry into the suit, as such water will warm inside the suit, and provide insulation. This perception is incorrect, since heat transfers via conduction, convection and radiation and any water inside the suit would increase conduction, as water is some 25 times more conductive than air. Also, any water ingress into the suit would increase heat loss via convection. Thus, it is prudent to minimize the entry of any water into the wetsuit to ensure maximum thermal insulation. However, for drysuits and survival suits it is imperative that such suits remain dry, as any leak into the suit is potentially dangerous, and at best, would greatly reduce the suit's thermal insulation, which insulation is generally a woollen undergarment, which should not become wet. Also, any ingress of water into a drysuit or survival suit would change the suit's buoyancy, potentially endangering the user. Accordingly, most modern drysuits and survival suits seal against the skin at the neck, wrists and ankles by using a thin elastomeric material, such as neoprene, latex or silicone, which material is tightly stretched over the skin. Such prior art seals have openings with an inner circumference that is about 35% undersized so as to provide a highly compressive seal against the skin when donned by the user. For example, a user with a neck circumference of 42 cm, would use a neck seal with on (unstretched) circumference of about 27 cm. This high level of compression against the skin, especially at the neck, can be very uncomfortable, and restrictive for head movement. Also, the use of a highly undersized appendage opening requires the sleeve/cuff to be significantly stretched during donning or doffing, which stretching thins such material, making it more prone to tearing. For example, a 35% undersized seal at the neck needs to be stretched about 130% to fit over the head. Thus, creating a comfortable, effective drysuit or survival suit seal is a challenge, especially at the neck, since such a seal cannot be too tight. Wetsuits generally leak somewhat, as the seals at the neck, wrists and ankles are comprised of neoprene foam with only modest compression against the skin surface, although some prior an discloses means for reducing such water ingress.
The prior art also generally discloses using “smooth surfaces” to facilitate reduced friction during suit donning and doffing, thus allowing easier entry of the head, hands and feet through the relevant constricted elastomeric openings. For example, neoprene wetsuits are often lined on the skin side with a stretchy layer of nylon/spandex, or a low friction coating, to increase tear resistance and to minimal friction against the skin during donning and doffing of the suit. In a further effort to reduce friction at the neck, ankles and wrists, the prior art discloses the use of relatively short seals, which shorter seals would reduce the overall sealing integrity. Ideally, coefficient of friction between the skin and overlying elastomeric layer should be as high as possible, thereby preventing the elastomeric layer from sliding along the skin during active engagement by the user, and thus potentially allowing water ingress. Also, the use of a longer sleeve contacting the skin would be beneficial for minimizing water ingress.
Another key aspect of wetsuits, drysuits and survival suits is easy entry and exit (i.e. donning and doffing) into and from the suit. To accommodate such donning and doffing issues, most modern wetsuits, drysuits and survival suits are designed to be either one-piece with a zipper for entry, or two-piece, where the two parts are sealed at the torso using, for example, a 360 degree zipper, multiple folds, connecting rings and/or belts or other materials encircling the torso. With the advent of reliable waterproof zippers, the use of one-piece suits now dominate commercially. Such zippers should preferably provide a sufficiently large opening for a person to don and doff the suit without help. However, zippers are not stretchy, and as such, their use greatly reduces overall suit stretch, making donning or doffing such a suit more difficult, especially for persons with restricted flexibility. Also, zippers tend to be expensive to install, and are prone to becoming stiff over time do to failure, corrosion or salt/dirt ingress, if not carefully maintained.
Various prior an exists disclosing wetsuits and drysuits with zippers. For example, U.S. Pat. No. 3,731,319 to O'Neill describes a wetsuit that has zipper across the back between the shoulders for entry and exit. U.S. Pat. No. 4,464,705 to Long, et. al. discloses a drysuit with a long diagonal zipper across the front for easy access. This patent also discloses an embodiment whereby the suit length can be adjusted to fit the diver's height once donned, where such adjustment is accomplished by folding over the excess length of the upper section at the torso. U.S. Pat. No. 5,802,609 to Garofalo shows a zipper design similar to the O'Neill patent, with the zipper located across the back. U.S. Pat. No. 6,415,449 B2 to Duplock shows a method of entry via a waterproof zipper shaped like a horseshoe around the neck seal, making closure of such a zipper location awkward. For ease of use, zippers should be installed at the front as zippers mounted oil the back are more difficult to access for opening and closing the suit. However, for suits for surfers, the zipper is generally installed in the back, as lying prune on a surfboard on top of a zipper is uncomfortable.
Some prior art has disclosed designs for one-piece wetsuits without zippers. For example, U.S. Pat. No. 5,768,703 to Machado discloses a double collar upper entry with an inner stretchable collar to allow the wearer to enter the suit without a zipper. An outer collar can be extend over the head of the wearer to seal against the wearer's neck. U.S. Pat. No. 5,896,578 to Hunter, et. al. also discloses a neck-entry wet suit, whereby a V-shaped cut-out enlarges the neck opening for entry, and seals such opening with a collar panel, using hooks and loops to secure closure of the panel. However, these designs require folding flaps, and mechanical means to hold such folds, to prevent water ingress at the neck, and as such, are not truly waterproof.
For donning or doffing a wetsuit, drysuit or survival suit, it is, in theory, more practical to use a two-piece suit overlapped at the torso. Such a suit can better fitter persons of different height, and one can don the top and bottom halves separately, which scenario is also highly beneficial in cases requiring urgent voiding. Doffing and donning of the suit is also far simpler, requiring minimum flexibility. Additionally, the frictional forces against the skin are reduced as each section can be donned or doffed separately. Accordingly, various prior art has been published disclosing two-piece wetsuits, dry suits and survival suits without zippers. For example, U.S. Pat. No. 2,570,019 to Wolk discloses what is essentially a drysuit for divers where the a jacket and pants are comprised of soft and flexible rubber which overlap at the waist, and which two parts can be joined by multiple overlapping folds. Such folds are held together by two interlocking bells. Sealing at the hands and head are accomplished by stretching highly elastic material to cling closely to the hands and head. U.S. Pat. No. 4,535,477 to Musto, et. al. discloses a two piece drysuit which is comprised of trousers and a jacket, which are sealed at the waist by rolling up annular rubber sealing flaps attached to the waist of the trousers and the bottom edge of the jacket. The two flaps are rolled up together and held in place by a separate tight fitting belt to prevent unrolling. US Patent Application 2013/0254963 A1 to Milezarczyk, et al. discloses a two-piece drysuit comprised of a trouser and top jacket, which parts can be interconnected at the waist using a so-called rolled seal. This application illustrates various configurations for overlapping the lop and lower suit flaps to improve the watertight seal, and also provides means to prevent the overlapping waist sealing flaps from disengaging during normal use. They further disclose at least one surface that is substantially smooth to form a good watertight seal with adjacent smooth surfaces of combined sealing flaps.
Another key aspect of wetsuits, drysuits and survival suits, irrespective of the suit being one-piece or two-piece, is the requirement to effectively, and comfortably, seal at the neck, wrists and ankles. Various prior art has been published to address such sealing requirements. For example, U.S. Pat. No. 3,731,315 to O'Neill describes a wetsuit with in-turned seals at the neck, ankles and wrist to form a substantially water tight seal. U.S. Pat. No. 4,365,351 to Doerschuk et. al. discloses a neck and wrist seal for use in a diving suit, which seals are comprised of open-cell neoprene foam with ail impervious skin layer on the inner surface, where such seals are sized to allow the user to push through the head or wrist, forming what is essentially a standard pressure seal. U.S. Pat. No. 5,196,240 to Stockwell discloses a seamless bodysuit for use as a wetsuit, drysuit or biohazard suit, which suit is formed by spraying an elastomeric material onto a textile substrate formed over a mannequin. Sealing at the wrist, ankle and neck openings is accomplished by overlapping the ends and covering with sprayed elastomeric material to provide an inside rubber seal. An adjustable external strap can be used to adjust the closure. U.S. Pat. No. 5,647,059 to Uglene, et al. discloses an inflatable neck seal sandwiched between a compressible material on the outside and a non-compressible material on the inside. Inflation of the seal deforms the inner compressible material to create a seal against the neck. U.S. Pat. No. 5,802,609 to Garofalo also discloses a similar sealing approach for use in a drysuit, whereby the suit sleeves, trousers and neck are folded inwards and stitched to form a tubular pocket containing an elastomeric beading. Similarly, U.S. Pat. No. 6,415,449 B2 to Duplock shows neck, ankle and wrist seals for a drysuit, where such seals use elastic material to fit closely against the skin to achieve a watertight seal. U.S. Pat. No. 6,668,386 B2 to Vidal discloses an adjustable neck seal for use in a drysuit, whereby an elastomeric pull cord is positioned within a tube encircling the neck opening, which cord can be tensioned to create a seal around the neck. U.S. Pat. No. 7,062,786 B2 to Stinton discloses a protective suit for use by divers, for survival or for protection from hazardous materials. Such suit uses water tight releasable seals at the waist, wrist, ankles and neck by using complementary shaped annular interlocking seal members extruded from polymeric material, with a second compressible polymeric material used to provide the seal. U.S. Pat. No. 7,313,829 B1 to Serra, et. al. discloses a novel reactive seal where a super absorbent water-swellable polymer blend, comprised of sodium polacrylate and poly-anionic beads is used to provide a neck, wrist and ankle seal by expanding upon contact with water, which expansion creates a pressure against a thin elastomeric membrane overlying the skin surface. However, these water swellable polymer beads are not actively reversible, and would need to be replaced after each use. Also, accidentally contacting water, for example, from spray or rain, would activate the beads, which activation is irreversible. US Patent Application 2007/0067886 A1 to Hunter, et. al., discloses a flexible neck seal for use in a wetsuit, whereby the closure is provided by the compressible seal between the flexible neck and wetsuit exterior, which compressive seal is induced by the tensile forces between specific anchor points on the exterior back and front of the wetsuit.